Sure: The book I mentioned earlier (A Beginner's Book of TeX by Seroul and Levy) is my favourite learning resource. You may able to find it in a library, or wherever you look for books. (There are other books available for free online, such as A Gentle Introduction to TeX (http://texdoc.net/texmf-dist/doc/plain/gentle/gentle.pdf) and TeX for the Impatient (http://mirrors.ctan.org/info/impatient/book.pdf).)

If all you have is a passing curiosity though, you may just want to look at some examples: Knuth has .tex sources of some of his papers on his website (https://cs.stanford.edu/~knuth/preprints.html); you can look at them and compare with the resulting PDF files (which you can generate with `pdftex`). For an already typeset example, look at JRM2680.tex (https://cs.stanford.edu/~knuth/papers/JRM2680.tex) and JRM2680.pdf (https://cs.stanford.edu/~knuth/papers/JRM2680.pdf).